paper-card.html

<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
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subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../paper-material/paper-material.html">

<!--
Material Design: <a href="http://www.google.com/design/spec/components/card.html">Cards</a>

`paper-card` is a container with a drop shadow.

Example:

    <paper-card heading="Card Title">
      <div class="card-content">Some content</div>
      <div class="card-actions">
        <paper-button>Some action</paper-button>
      </div>
    </paper-card>

### Accessibility

By default, the `aria-label` will be set to the value of the `heading` attribute.

### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-card-header-color` | The color of the header text | `#000`
`--paper-card-header` | Mixin applied to the card header section | `{}`
`--paper-card-content` | Mixin applied to the card content section| `{}`
`--paper-card-actions` | Mixin applied to the card action section | `{}`
`--paper-card` | Mixin applied to the card | `{}`

@group Paper Elements
@element paper-card
@demo demo/index.html
-->

<dom-module id="paper-card">
  <style>
  :host {
    display: inline-block;
    position: relative;
    box-sizing: border-box;

    background: #fff;
    border-radius: 2px;
    @apply(--paper-card);
  }

  /* IE 10 support for HTML5 hidden attr */
  [hidden] {
    display: none !important;
  }

  .header {
    position: relative;
    @apply(--paper-card-header);
  }

  .header img {
    width: 100%;
    pointer-events: none;
  }

  .header .title-text {
    padding: 16px;
    font-size: 24px;
    font-weight: bold;
    color: var(--paper-card-header-color, #000);
  }

  .header .title-text.over-image {
    position: absolute;
    bottom: 0px;
  }

  :host ::content .card-content {
    padding: 16px;
    position:relative;
    @apply(--paper-card-content);
  }

  :host ::content .card-actions {
    border-top: 1px solid #e8e8e8;
    padding: 5px 16px;
    position:relative;
    @apply(--paper-card-actions);
  }

  </style>

  <template>

    <paper-material id="shadow" animated$="[[animatedShadow]]" elevation=[[elevation]]>
      <div class="header">
        <img hidden$="[[!image]]" src="[[image]]">
        <div hidden$="[[!heading]]" class$="[[_computeHeadingClass(image)]]">[[heading]]</div>
      </div>

      <content></content>

    </paper-material>

  </template>

</dom-module>

<script>

  Polymer({

    is: 'paper-card',

    properties: {

      /**
       * The title of the card.
       */
      heading: {
        type: String,
        value: '',
        observer: '_headingChanged'
      },

      /**
       * The url of the title image of the card.
       */
      image: {
        type: String,
        value: ''
      },

      /**
       * The z-depth of the card, from 0-5.
       */
      elevation: {
        type: Number,
        value: 1
      },

      /**
       * Set this to true to animate the card shadow when setting a new
       * `z` value.
       */
      animatedShadow: {
        type: Boolean,
        value: false
      }
    },

    _headingChanged: function(heading) {
      var label = this.getAttribute('aria-label');
      this.setAttribute('aria-label', heading);
    },

    _computeHeadingClass: function(image) {
      var cls = 'title-text';
      if (image)
        cls += ' over-image';
      return cls;
    }
  });
</script>